[UX] Improve connection selection UI

[adeacetis]

Is your feature request related to a problem? Please describe.

As a user, I would like to add connections efficiently.

Describe the solution you'd like

When an exchange is selected, and I click on a type of product. The list should never be empty. If the exchange doesn't offer the product, I want the type filtered out.

By default, all types must be selected.

If the user unchecks the options, then the connections list must be empty.

Likewise with quote currencies, if the exchange doesn't offer a quote currency, it shouldn't be listed.

Nice to have:
A counter visible next to the attributes name shows how many pairs are actually available

Describe alternatives you've considered

/